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title: Pocket C.H.I.P.
tags: debian chip hack 100daystooffload
date: 2021-02-24
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Intro

Recently I got a Pocket C.H.I.P. with the idea of making it mini
terminal on my desk, displaying things like weather, new email, new
mastodon toots, etc. It comes pre-loaded with some basic software:
terminal, pico8, and a few other utilities. Because it was released in
2017 and the demise of the original Next Thing the software on it is
out-of-date, running Debian 8 and an older version of pico8.

 [Pocket C.H.I.P.]: https://shop.pocketchip.co/
 [pico8]: https://www.lexaloffle.com/pico-8.php

[Pocket C.H.I.P.]

 [1]: /assets/images/posts/pocket-chip.png

Pocket C.H.I.P.
I wanted to updated it to at least Debian 10, and found a working
guide which follows the basic Debian upgrade process as well as some
fixes for common issues like Xorg configs and updating wifi settings.

 [working guide]: https://gist.github.com/luzhuomi/526fbcc30f3522f09eacf20d0f776fa5

Unfortunately this broke a few other things that weren’t listed in the
guide, like the FN keys no longer working on the built-in keyboard and
pico8 failing to start. I spent some time tackling these issues and
now have a fully working Debian 10 Pocket C.H.I.P. with pico8 and a
functioning keyboard.

Fixing FN Keys

After upgrading to Debian 10, the FN keys on the C.H.I.P. build-in
keyboard will no longer work. Fix this by sourcing the keymap in
/home/chip/.xinitrc and restarting C.H.I.P. for xorg to load the
xmodmap every time.

   [[ -f /home/chip/.Xmodmap ]] && xmodmap /home/chip/.Xmodmap

For reference /home/chip/.Xmodmap is,

   keycode 10 = 1 exclam F1 exclam
   keycode 11 = 2 at F2 at
   keycode 12 = 3 numbersign F3 numbersign
   keycode 13 = 4 dollar F4 dollar
   keycode 14 = 5 percent F5 percent
   keycode 15 = 6 asciicircum F6 asciicircum
   keycode 16 = 7 ampersand F7 ampersand
   keycode 17 = 8 asterisk F8 asterisk
   keycode 18 = 9 parenleft F9 parenleft
   keycode 19 = 0 parenright F10 parenright
   keycode 22 = BackSpace BackSpace KP_Delete BackSpace
   keycode 29 = y Y braceleft Y
   keycode 30 = u U braceright U
   keycode 31 = i I bracketleft I
   keycode 32 = o O bracketright O
   keycode 33 = p P bar P
   keycode 36 = Return NoSymbol KP_Enter
   keycode 43 = h H less H
   keycode 44 = j J greater J
   keycode 45 = k K apostrophe K
   keycode 46 = l L quotedbl L
   keycode 56 = b B grave b
   keycode 57 = n N asciitilde n
   keycode 58 = m M colon M
   keycode 59 = comma less semicolon less
   keycode 60 = period comma semicolon comma
   keycode 61 = slash question backslash question
   keycode 82 = KP_Subtract underscore F11 KP_Subtract
   keycode 86 = KP_Add KP_Equal F12 KP_Add
   keycode 108 = Mode_switch Meta_R Alt_R Meta_R
   keycode 111 = Up NoSymbol Prior
   keycode 113 = Left NoSymbol Home
   keycode 114 = Right NoSymbol End
   keycode 116 = Down NoSymbol Next

Updating Pico8

Downloaded latest Pico8 for the C.H.I.P. from lexaloffle.com and
follow the instructions on installing it.

 [lexaloffle.com]: https://www.lexaloffle.com/bbs/?tid=34009

The binary was built against an old version of libcurl and will give
error about not finding CURL_OPENSSL_3.

   ./pico8: /usr/lib/arm-linux-gnueabihf/libcurl.so.4: version `CURL_OPENSSL_3' not found (required by ./pico8)

To fix this, download the older Raspian Stretch image and mount it
locally

 [Raspian Stretch image]: https://downloads.raspberrypi.org/raspbian/images/raspbian-2017-09-08/

   sudo mount -v -o offset=48234496 -t ext4 2017-09-07-raspbian-stretch.img /mnt

Create the directory /usr/local/share/libcurlhack and copy the files
/mnt/usr/lib/arm-linux-gnueabihf/{libcrypto.so.1.0.2,libcurl.so.4,libssl.so.1.0.2}
from the Raspbian Stretch image to the C.H.I.P.

When finished the C.H.I.P. /usr/local/share/libcurlhack/ will look
like this,

   chip@chip:~$ ls -l /usr/local/share/libcurlhack/
   total 2208
   -rw-r--r-- 1 root staff 1493272 Feb 24 02:20 libcrypto.so.1.0.2
   -rw-r--r-- 1 root staff  439956 Feb 24 02:15 libcurl.so.4
   -rw-r--r-- 1 root staff  320924 Feb 24 02:19 libssl.so.1.0.2

Create a shell script /usr/local/bin/pico8 that will include this new
path in LD_LIBRARY_PATH,

   #!/bin/sh

   LD_LIBRARY_PATH=/usr/local/share/libcurlhack:/usr/lib/arm-linux-gnueabihf/
   export LD_LIBRARY_PATH

   /usr/lib/pico8/pico8

Running Pico8 from the Pocket C.H.I.P. launcher will now work.

Changing the Window Manager

By default the C.H.I.P. will run the pocket-wm, which is a modified
version of dwm.

 [dwm]: https://dwm.suckless.org/

   chip@chip:/usr/share/xsessions$ pocket-wm -v
   dwm-6.0, © 2006-2011 dwm engineers, see LICENSE for details

This in turn runs dmenu and to launch the “home” screen with the
applications Iceweasel, pico8, urxvt, and aeabi.

 [dmenu]: https://tools.suckless.org/dmenu/

   chip@chip:~$ strings /usr/bin/pocket-wm | grep dmenu_run -A4
   dmenu_run
   Iceweasel
   pico8
   urxvt
   aeabi

I looked a bit to see how all this was configured, but need to spent
more time on reading up on dwm and dmenu_run to know what I’m looking
at.

To run a different window manager or session we’ll need to configure
Lightdm to use something other than pocket-wm.

 [Lightdm]: https://github.com/canonical/lightdm

For example to run Fluxbox, install it using apt,

 [Fluxbox]: http://fluxbox.org/

   sudo apt-get update && sudo apt-get install -y fluxbox

Which creates fluxbox.desktop in /usr/share/xsessions. This directory
contains all available window managers that Lightdm can launch.

   chip@chip:~$ ls -l /usr/share/xsessions
   total 24
   -rw-r--r-- 1 root root  188 Feb 26  2019 awesome.desktop
   -rw-r--r-- 1 root root  222 Feb 24  2014 fluxbox.desktop
   -rw-r--r-- 1 root root   86 Feb 22  2019 lightdm-xsession.desktop
   -rw-r--r-- 1 root root  118 Apr 27  2016 pocket-wm.desktop
   -rw-r--r-- 1 root root 5465 Oct 21  2017 xfce.desktop

In the chip users home directory ~/.dmrc and set Session= to the
window manager lightdm should launch automatically. This will match
what’s in /usr/share/xessions but without the .desktop extension This
will match what’s in /usr/share/xessions but without the .desktop
extension.

   [Desktop]
   Language=en_US.utf8
   Session=fluxbox

Restart lightdm and it will restart the C.H.I.P. with the new window
manager.

   sudo systemctl restart lightdm

[Fluxbox on PocketCHIP]

 [Fluxbox on PocketCHIP]: /assets/images/posts/fluxbox-chip.png

Fluxbox on PocketChip
Right Click

Right click is heavily used on Fluxbox but doesn’t work out-of-the-box
with the Pocket C.H.I.P., and setting a button override in Xmodmap or
mouse keys in Xorg doesn’t work (it even seems to break the FN keys).
To enable right click by holding down on the touch screen build and
setup evdev-right-click-emulation.

 [evdev-right-click-emulation]: https://github.com/PeterCxy/evdev-right-click-emulation

   # Clone the repoistory
   git clone https://github.com/PeterCxy/evdev-right-click-emulation

   # Install required dependencies to build
   sudo apt-get install -y libevdev-dev libevdev2

   # Build evdev-rce
   make all

   # Move evdev-rce to a system path and chown the owner group
   sudo mv out/evdev-rce /usr/local/bin
   sudo chown root:staff /usr/local/bin/evdev-rce

   # Have evdev-rce start on boot
   echo "/usr/local/bin/evdev-rce &" | sudo tee -a /etc/rc.local

Conclusion

the Pocket C.H.I.P. is a lot of fun, even with some of these issues
the troubleshooting process gave me a way to explore the system and
understand how it works. This is valuable as I continue to tinker with
it to make it a true desk mini-terminal.

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